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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*/
#ifndef __ASM_ARC_CMPXCHG_H
#define __ASM_ARC_CMPXCHG_H
#include <linux/build_bug.h>
#include <linux/types.h>
#include <asm/barrier.h>
#include <asm/smp.h>
#ifdef CONFIG_ARC_HAS_LLSC
/*
* if (*ptr == @old)
* *ptr = @new
*/
#define __cmpxchg(ptr, old, new) \
({ \
__typeof__(*(ptr)) _prev; \
\
__asm__ __volatile__( \
"1: llock %0, [%1] \n" \
" brne %0, %2, 2f \n" \
" scond %3, [%1] \n" \
" bnz 1b \n" \
"2: \n" \
: "=&r"(_prev) /* Early clobber prevent reg reuse */ \
: "r"(ptr), /* Not "m": llock only supports reg */ \
"ir"(old), \
"r"(new) /* Not "ir": scond can't take LIMM */ \
: "cc", \
"memory"); /* gcc knows memory is clobbered */ \
\
_prev; \
})
#define arch_cmpxchg_relaxed(ptr, old, new) \
({ \
__typeof__(ptr) _p_ = (ptr); \
__typeof__(*(ptr)) _o_ = (old); \
__typeof__(*(ptr)) _n_ = (new); \
__typeof__(*(ptr)) _prev_; \
\
switch(sizeof((_p_))) { \
case 4: \
_prev_ = __cmpxchg(_p_, _o_, _n_); \
break; \
default: \
BUILD_BUG(); \
} \
_prev_; \
})
#else
#define arch_cmpxchg(ptr, old, new) \
({ \
volatile __typeof__(ptr) _p_ = (ptr); \
__typeof__(*(ptr)) _o_ = (old); \
__typeof__(*(ptr)) _n_ = (new); \
__typeof__(*(ptr)) _prev_; \
unsigned long __flags; \
\
BUILD_BUG_ON(sizeof(_p_) != 4); \
\
/* \
* spin lock/unlock provide the needed smp_mb() before/after \
*/ \
atomic_ops_lock(__flags); \
_prev_ = *_p_; \
if (_prev_ == _o_) \
*_p_ = _n_; \
atomic_ops_unlock(__flags); \
_prev_; \
})
#endif
/*
* xchg
*/
#ifdef CONFIG_ARC_HAS_LLSC
#define __xchg(ptr, val) \
({ \
__asm__ __volatile__( \
" ex %0, [%1] \n" /* set new value */ \
: "+r"(val) \
: "r"(ptr) \
: "memory"); \
_val_; /* get old value */ \
})
#define arch_xchg_relaxed(ptr, val) \
({ \
__typeof__(ptr) _p_ = (ptr); \
__typeof__(*(ptr)) _val_ = (val); \
\
switch(sizeof(*(_p_))) { \
case 4: \
_val_ = __xchg(_p_, _val_); \
break; \
default: \
BUILD_BUG(); \
} \
_val_; \
})
#else /* !CONFIG_ARC_HAS_LLSC */
/*
* EX instructions is baseline and present in !LLSC too. But in this
* regime it still needs use @atomic_ops_lock spinlock to allow interop
* with cmpxchg() which uses spinlock in !LLSC
* (llist.h use xchg and cmpxchg on sama data)
*/
#define arch_xchg(ptr, val) \
({ \
__typeof__(ptr) _p_ = (ptr); \
__typeof__(*(ptr)) _val_ = (val); \
\
unsigned long __flags; \
\
atomic_ops_lock(__flags); \
\
__asm__ __volatile__( \
" ex %0, [%1] \n" \
: "+r"(_val_) \
: "r"(_p_) \
: "memory"); \
\
atomic_ops_unlock(__flags); \
_val_; \
})
#endif
#endif
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